1. Field of the Invention
This invention relates to a device for converting relatively small units of thermal energy into a working mechanical force, said transformation being accomplished in an extremely economical manner.
2. Description of the Prior Art
Various forms of thermal motors for converting heat energy into mechanical motion are known in the prior art. In recent years, no doubt due to the recurring energy crises facing the United States, the interest in such devices has been significantly rekindled. Such prior art devices almost inevitably comprise a structure whereby heat is used to create an imbalance resulting in rotary motion of a drive shaft-type member.
For example, many prior art devices teach the use of volatile liquid as the mass utilized to create an imbalance. Heat is applied to the liquid causing it to volatize and move to a position which is eccentric with respect to the drive shaft. Other prior art devices teach the use of metallic elements wherein the metal has an unusually high coefficient of linear expansion. In these devices heating the metallic element causes it to expand, resulting in the displacement of a weight attached to the metallic element. Still other prior art devices teach the use of a gas or liquid as an exhaust fluid to assist in maintaining the angular velocity of a rotating drive shaft.
However, such prior art devices have generally proved to be unsuitable for the performance of any meaningful work. The structures themselves are often times so large and complicated that they are much more expensive than the benefits derived therefrom. In systems utilizing liquids it has been necessary to provide a constant replenishment source for the liquid so that the device will continue to operate. Devices utilizing expanding metallic elements are quite obviously extremely subject to the deleterious effects of their environment. That is to say, when exposed to the atmosphere for prolonged periods of time the metallic elements corrode, necessarily resulting in loss of efficiency. However, perhaps the greatest problem encountered with prior art devices lies not in heating the conversion material, but rather in cooling it so that the cycle may be repeated.
Accordingly, it is obvious that there is a great need in the art for a reliable, economical means of transforming thermal energy into a useful work force. Such a device should be of relatively simple construction, and should define a closed system so that all that is required for its operation is a continuous source of thermal energy. And, of course, the device must include means for rapidly cooling the conversion material so that the transformation cycle may be repeated to provide a constant mechanical force. Finally, the energy converter must be compatible with a wide variety of thermal energy sources, such a solar energy, industrial waste heat, lasers, electricity, and flames.